Loosen python version restrictions, and add matrix of tests for diffe…

[blackary]

…rent python versions

[arnaudmiribel]

Surprised we're not using some type hints that could throw exceptions... but let's see!

[tylerjrichards]

found out why Streamlit 3.9.7 doesn't work for future reference streamlit/streamlit#5140

[tylerjrichards]

found out why Streamlit 3.9.7 doesn't work for future reference streamlit/streamlit#5140

you two probably knew this already!

[blackary]

@arnaudmiribel 3.7 does have some typing issues, but not 3.8+

 > mypy --python-version 3.7
src/streamlit_extras/badges/__init__.py:1: error: Module "typing" has no attribute "Literal"; maybe "_Literal"?
src/streamlit_extras/badges/__init__.py:1: error: Module "typing" has no attribute "get_args"
src/streamlit_extras/badges/__init__.py:9: error: Variable "streamlit_extras.badges._SUPPORTED_TYPES" is not valid as a type
src/streamlit_extras/badges/__init__.py:9: note: See https://mypy.readthedocs.io/en/stable/common_issues.html#variables-vs-type-aliases
src/streamlit_extras/function_explorer/__init__.py:2: error: Module "typing" has no attribute "get_args"
src/streamlit_extras/colored_header/__init__.py:3: error: Module "typing" has no attribute "Literal"; maybe "_Literal"?
src/streamlit_extras/colored_header/__init__.py:161: error: Variable "streamlit_extras.colored_header._SUPPORTED_COLORS" is not valid as a type
src/streamlit_extras/colored_header/__init__.py:161: note: See https://mypy.readthedocs.io/en/stable/common_issues.html#variables-vs-type-aliases